#include <bits/stdc++.h>

using namespace std;
int n,p;
char s1[10010];
char endh[10010],sta[10010];
string ans;
int main(){
	cin>>n;
	for(int i = 1;i<=n;i++){
		cin>>s1[i];
	}
	cin>>p;
	for(int i = 1;i<=n;i++){
		endh[i] = s1[i];//取末位 
	}
	sort(s1+1,s1+1+n);
	for(int i = 1;i<=n;i++){
		sta[i] = s1[i];//取首位 
	}
	cout<<(char)endh[p];
	int lc = p;
	int ent = 1;
	while(1){
		cout<<(char)sta[lc];
	
		ent++;
		if(ent == n) return 0;
		for(int i = 1;i<=n;i++){
			if((int)endh[i] == (int)sta[lc]){
				lc = i;
				break;
			}
		}
	}
	
	
	return 0;
}

样例过了，#1TLE #3-#10WA